content/browser/preloading/prefetch/prefetch_url_loader_interceptor.h

// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_PRELOADING_PREFETCH_PREFETCH_URL_LOADER_INTERCEPTOR_H_
#define CONTENT_BROWSER_PRELOADING_PREFETCH_PREFETCH_URL_LOADER_INTERCEPTOR_H_

#include <memory>

#include "base/memory/weak_ptr.h"
#include "base/sequence_checker.h"
#include "content/browser/loader/navigation_loader_interceptor.h"
#include "content/common/content_export.h"
#include "content/public/browser/global_routing_id.h"
#include "services/network/public/cpp/resource_request.h"

namespace content {

class BrowserContext;
class PrefetchContainer;

// Intercepts navigations that can use prefetched resources.
class CONTENT_EXPORT PrefetchURLLoaderInterceptor
    : public NavigationLoaderInterceptor {
 public:
  static std::unique_ptr<PrefetchURLLoaderInterceptor> MaybeCreateInterceptor(
      int frame_tree_node_id,
      const GlobalRenderFrameHostId& referring_render_frame_host_id);

  PrefetchURLLoaderInterceptor(
      int frame_tree_node_id,
      const GlobalRenderFrameHostId& referring_render_frame_host_id);
  ~PrefetchURLLoaderInterceptor() override;

  PrefetchURLLoaderInterceptor(const PrefetchURLLoaderInterceptor&) = delete;
  PrefetchURLLoaderInterceptor& operator=(const PrefetchURLLoaderInterceptor&) =
      delete;

  // NavigationLoaderInterceptor
  void MaybeCreateLoader(
      const network::ResourceRequest& tentative_resource_request,
      BrowserContext* browser_context,
      NavigationLoaderInterceptor::LoaderCallback callback,
      NavigationLoaderInterceptor::FallbackCallback fallback_callback) override;

 protected:
  int GetFrameTreeNodeId() const { return frame_tree_node_id_; }

 private:
  // Gets the `PrefetchContainer` (if any) to be used for
  // `tentative_resource_request`. The `PrefetchContainer` is first obtained
  // from `PrefetchService` and then goes through other checks in
  // `PrefetchUrlLoaderHelper`.
  // The |get_prefetch_callback| is called with this associated prefetch.
  // Declared virtual only for testing.
  virtual void GetPrefetch(
      const network::ResourceRequest& tentative_resource_request,
      base::OnceCallback<void(base::WeakPtr<PrefetchContainer>)>
          get_prefetch_callback) const;

  void OnGetPrefetchComplete(
      base::WeakPtr<PrefetchContainer> prefetch_container);

  // The frame tree node |this| is associated with, used to retrieve
  // |PrefetchService|.
  const int frame_tree_node_id_;

  // Corresponds to the ID of "navigable's active document" used for "finding a
  // matching prefetch record" in the spec. This is used as a part of
  // `PrefetchContainer::Key` to make prefetches per-RenderFrameHost.
  // https://wicg.github.io/nav-speculation/prefetch.html
  // TODO(https://crbug.com/1431804): This is not strictly per-Document.
  const GlobalRenderFrameHostId referring_render_frame_host_id_;

  // Called once |this| has decided whether to intercept or not intercept the
  // navigation.
  NavigationLoaderInterceptor::LoaderCallback loader_callback_;

  // The prefetch container that has already been used to serve a redirect. If
  // another request can be intercepted, this will be checked first to see if
  // its next redirect hop matches the request URL.
  base::WeakPtr<PrefetchContainer> redirect_prefetch_container_;

  SEQUENCE_CHECKER(sequence_checker_);

  base::WeakPtrFactory<PrefetchURLLoaderInterceptor> weak_factory_{this};
};

}  // namespace content

#endif  // CONTENT_BROWSER_PRELOADING_PREFETCH_PREFETCH_URL_LOADER_INTERCEPTOR_H_